Fusion warheads:
As regards nuclear dampers affecting pure fusion warheads,
it depends on how these work as opposed to fusion power plants. Such
warheads would have to be uncontrolled fusion reactors (as conventional
explosives will not be able to conceivably reach the required temperatures
and pressures). Until the reactor is actually triggered, nothing happens.
A nuclear damper stops fission warheads because it turns the unstable
heavy elements in it to lead. The fuel is zapped.
The old fuel problem now raises its ugly head - what would be used to
fuel a pure fusion weapon? What does a nuclear damper to to low-number
unstable isotopes like Deuterium and Tritium? There is no indication that
dampers have ANY effect on fuel in starships, and such warheads could use
the same fuel, even if it means a bigger weapon. If dampers could stop fusion
reactions this would have been mentioned, as it would be quite important.
(Nuclear damper spinal mounts? The mind boggles).
A possible out is that a pure fusion bomb would have to be very large, as
it would have to fuse a significant amount of fuel in it's brief operating
lifetime. In effect, it would be a very high-yield fusion power plant.
Such devices would have limited utility if they had to be the size of
starship power plants to have a useful yield. Difficult for point-defences
to miss :-). This would explain why they are not used. However, they would
make nice mines(one multi-gigaton bomb can spoil your whole day).
Ice refuelling:
While going out and mining ice is perfectly possible, whether
with lasers or with axes and hard labour, there could be an easier solution.
One thing starships do not lack is power. So just radiate some heat and
melt the ice before pumping it in. A giant electric blanket could do this and
prevent the water from escaping. If the ice is on a significant body like a
planet things are even simpler - starship weaponry can melt a lot of ice,
if messily. However, Scott and Steve, your methods are much healthier from
the exercise point of view, so you can keep on digging :-).
By the way, in my part of damp, rainy Ireland fortunately snow and ice are
pretty rare. Maybe the only good thing about the weather over here.
Tom.